Harold Shipman, the former GP who is believed to have killed more than 200 people, has been found dead in his prison cell.

He was found hanging by a bed sheet strung around the bars of his cell at Wakefield Prison at 0620 GMT. Prison staff tried to revive him but he was pronounced dead at 0810 GMT.

Shipman, who hanged himself in his cell on the eve of his 58th birthday, was one of 563 inmates at the jail, regarded as one of the UK's best high-security prisons.

Prison officials have described his death as an "apparent suicide" and added he was taken off suicide watch 18 months ago. Shipman was on a standard security watch at the West Yorkshire jail at the time of his death.

The Prison Service said Shipman was "showing no signs whatsoever of pre-suicidal behaviour at all". The 57-year-old was behaving normally and there was "absolutely no indication" of the events to come, according to a spokeswoman.

Shortly after 1100 GMT, an undertaker's van took Shipman's body from Wakefield prison to the Medico Legal Centre in Sheffield for a post-mortem and formal identification.

Prisons Minister Paul Goggins said prisons ombudsman Stephen Shaw would carry out an investigation into Shipman's death. A separate police and coroner inquiry will also be carried out.

Shipman was jailed for life at Preston Crown Court in January 2000 for murdering 15 patients.

The murders took place between 1975 and 1998 with the victims dying from lethal injections administered by the doctor. His oldest victim was a 93-year-old woman and the youngest a 41-year-old man.

Dame Janet Smith, who ran the ensuing Shipman inquiry, reported in 2002 that she believed that over a period of 23 years he had killed 215 patients and there was a "real suspicion" that he had killed another 45.

I am shocked and surprised. I think there was a real possibility he would confess.

Bernard Postles, retired Greater Manchester Police detective

Shipman was serving 15 concurrent life sentences and had been told by the government he would never be allowed parole.

He had shown no remorse for - nor ever admitted to - his crimes, insisting he always delivered appropriate treatment to his patients. He was planning an appeal of the convictions when he died.

We have had many calls from our clients and they are in shock. There are more questions raised than answers.

Solicitor Anne Alexander

There have been calls for an investigation into how such a notorious inmate was apparently able to kill himself.

For 23 years, Shipman had convinced people in the close-knit Manchester suburb of Hyde that he was a good family doctor.

The GP preyed mainly on elderly women living alone as his victims and he often administered lethal injections on home visits. He worked for many years as a solo GP, free from the scrutiny of other doctors.

Shipman stockpiled diamorphine by issuing false prescriptions and retaining leftover supplies from patients, helped by an inadequate system for monitoring controlled drugs.

Over Christmas 2003, Shipman was put on "basic privileges" after he was uncooperative with staff. He would have had to wear prison uniform and would have had no TV in his cell. He was moved back to the "standard privilege" level a week before he died.